In the past, leading-edge commercial applications with high performance and reliability requirements were typically run on legacy systems, such as Information Management System (IMS). (IMS is a trademark of International Business Machines Corporation in the United States, other countries, or both.). Today, the near universal acceptance of Web Technologies increases the demands for communication-based applications; however, even in today's distributed computing environments with Web based applications, it is very common for the data associated with WEB based applications to be legacy data (i.e. data that is managed by legacy systems, such as IMS). Therefore, many enterprises are faced with the challenge of making core business applications currently running on legacy systems available to the Internet.
IMS is a hierarchical database management system (HDBMS) developed by International Business Machines Corporation with wide spread usage in many large enterprises where high transaction volume, reliability, availability and scalability are of the utmost importance. IMS provides software and interfaces for running the businesses of many of the world's largest corporations. However, companies incorporating IMS databases into their business models typically make significant investments in IMS application programs in order to have IMS perform meaningful data processing particularly tailored to the needs of their respective enterprises. IMS application programs are typically coded in COBOL, PL/I, C, PASCAL, JAVA or assembly language.
In one example, the typical components of a Web based application may comprise an application program to perform particular business logic, a client system including a web browser for entering data and displaying results, a Web server to provide communication and security layers around the customer application, a database adapter to facilitate application communications with a database subsystem for the processing of data requests. A user interfaces with a client system to view and/or process data in accordance with the their needs and the capabilities provided by the various enterprise applications. This results in the client system's web browser communicating with the Web server component using the HyperText Transfer Protocol (HTTP) over an Internet connection using Transmission Control Protocol/Internet Protocol (TCP/IP). The Web server identifies the appropriate application and schedules this application for execution. Upon receiving control, the application invokes the database adapter to communicate with the database subsystem to handle data requests.
New protocols have been developed by IMS to accommodate web-based applications requiring access to IMS data. However, in some computing network environments it may be necessary for a first DBMS (Database Management Subsystem) to communicate with a second DBMS. In some database environments, the first DBMS is referred to as the front-end DBMS and the second DBMS is referred to as the back-end DBMS. Whenever the back-end DBMS is non-IMS and the front-end DBMS is IMS a serious problem, briefly discussed infra, may arise.
A network message, representing a communication to IMS, may contain an internet message prefix which, among other information, contains routing information identifying address information associated with the client originating the information request. Eventually, any results associated with this request must be routed back to the originating client. However, when IMS, the front-end DBMS, is required to communicate with a non-IMS DBMS on the back-end, the internet message prefix may be discarded in some circumstances in conforming to the requirements of the particular network and back-end DBMS protocols.
In this set of circumstances, the result message generated by the back-end DBMS is routed back to the originating front-end DBMS; however, the result message may be void of routing information for the originating client request. If so, such a result message is referred to as an “orphaned” message, as it is not possible to return the message to the originating client.
Accordingly, there is a great need for an enhanced message routing facility that preserves client routing information contained in an internet message prefix within a computer network comprising heterogeneous databases.